1. Field of the Invention
The present invention relates to a piping fluid decision device adapted for a decision of a fluid state of a fluid substance such as a liquid flowing in a piping, and a piping fluid control system for controlling the fluid state of the fluid substance depending on result of the decision.
2. Description of Relevant Art
Conventionally, as an example of such a device, there is one decides a fluid state of beer in a piping for sending beer in a beer factory or food shop. For example, as shown in FIG. 1, electrodes 103 and 105 are inserted in a piping 101 for sending beer, and a decision is made on a fluid state of beer 107 flowing in the piping 101. The decision of the fluid state is made by detecting a conductivity in the piping 101 using the electrodes 103 and 105, and detecting a difference of conductivity between a liquid part 109 and a froth part 111 of the beer 107. Depending on a result of the decision, the froth part 111 of the beer 107 flowing in the piping 101 is wasted, as necessary, to surely take out the liquid part 109 of the beer.
Therefore, it is possible to take out beer 107 with little froth anytime from a take-out machine installed at a terminal of the piping 101.
However, in the conventional device of FIG. 1, beer 107 flowing in the piping 101 directly contacts the electrodes 103 and 105, thus easily leading to corrosion of the electrode 103 and 105, with a probable sanitary problem. As a variation of conductivity is detected, voltage variations to be small are necessarily integrated, with an increased calculation amount, as another problem. The detection by conductivity tends to be influenced by an associated magnetic field, and eliminates a disposition in a vicinity of an electromagnetic valve, as still another problem.
Further, if the fluid substance flowing in the piping .101 is a solid body such as a metallic flow, a soil flow, or a stone flow, the fluid substance may collide on the electrodes 103 and 105, causing the electrodes 103 and 105 to be damaged, leading to a probable failure of detection. Therefore, it was difficult, for a device having electrodes 103 and 105 inserted in a piping 101 like FIG. 1, to make a decision on a fluid state of a solid fluid substance.
The present invention has been made with such points in view. It therefore is an object of the present invention to provide a piping fluid decision device and a piping fluid control system that can surely and easily make a decision on a fluid state of a fluid substance flowing in a piping, irrespective of the kind, without sanitary problem.
To achieve the object, according to a first aspect of the invention, there is provided a piping fluid decision device comprising an electrostatic capacity sensor disposed outside of a piping adapted for a fluid substance to flow through a path therein, for detecting a variation of electrostatic capacity of the path in the piping, reference value storage means for storing in advance a reference variation of electrostatic capacity of the path to provide for a decision on a fluid state of the fluid substance flowing through the path in the piping, and fluid decision means for comparing the detected variation of electrostatic capacity and the stored variation of electrostatic capacity to make the decision on the fluid state of the fluid-substance flowing through the path.
According to a second aspect of the invention, in a piping fluid decision device according to the first aspect of the invention, the electrostatic capacity sensor comprises a measuring electrode and a grounding electrode made of a conductive metallic film and wound around an outside of the piping forming the path, with an insulator in between, and a shield member covering the measuring electrode and the grounding electrode, with an insulator in between.
According to a third aspect of the invention, in a piping fluid decision device according to the second aspect of the invention, the grounding electrode is narrower than the measuring electrode, and the measuring electrode and the grounding electrode are alternately disposed.
According to a fourth aspect of the invention, in a piping fluid decision device according to the third aspect of the invention, the measuring electrode and the grounding electrode are wound to be spiral along a flow direction.
Further to achieve the object, according to a fifth aspect of the invention, there is provided a piping fluid control system comprising a piping fluid decision device according to any of the first to fourth aspects of the invention, adjust means adapted to adjust the fluid state of the fluid substance flowing through the path, and control means for controlling the adjust means depending on a result of the decision of the fluid decision means.
According to a sixth aspect of the invention, in a piping fluid control system according to the fifth aspect of the invention, the piping is provided at a terminal thereof with a substance take-out machine of the fluid substance, the adjust means comprises a first open-close valve installed on the piping between an electrostatic capacity sensor position and a substance take-out machine position, and a second open-close valve installed on a branch pipe connected to the piping between a position of the first open-close valve and the electrostatic capacity sensor position, and the control means is adapted, when the variation of electrostatic capacity is within a set value, to open the first open-close valve and close the second open-close valve and, when the variation of electrostatic capacity exceeds the set value, to close the first open-close valve and open the second open-close valve.
According to the first aspect of the invention, for a fluid substance flowing through a path in a piping, a variation of electrostatic capacity of the path in the piping can be detected by an electrostatic capacity sensor. Reference value storage means can store in advance a reference variation of electrostatic capacity of the path to provide for a decision on a fluid state of the fluid substance flowing through the path in the piping. Fluid decision means can compare the detected variation of electrostatic capacity and the stored variation of electrostatic capacity to make the decision on the fluid state of the fluid substance flowing through the path.
Accordingly, a decision can surely be made of a fluid state in a piping, for example, such as on a normality or abnormality or of a change of kind of fluid substance. Moreover, fluid state of a fluid substance flowing through a path in a piping can be intact-decided, securing a sanitary condition even when the fluid substance is a food. Further, fluid state of a fluid substance flowing in a path can be decided by an electrostatic capacity or its variation, with a large voltage variation without needing an integration of detected values, and with a reduced calculation amount. As the fluid state is detected by a variation of electrostatic capacity, it hardly receive influences of a magnetic field. Even when the fluid substance is a slid body, such as a metallic flow, soil flow, stone flow, or the like, electrodes are kept from collision with the fluid substance, allowing for a fluid state of solid fluid substance to be surely and easily decided.
According to the second aspect of the invention, in addition to effects of the first aspect of the invention, a fluid state of a fluid substance in a piping can be surely and easily decided by a measuring electrode and a grounding electrode of a conductive metallic film wound in turns, securing a sanitary condition as well.
According to the third aspect of the invention, in addition to effects of the second aspect of the invention, because the grounding electrode is narrower than the measuring electrode and the measuring electrode and the grounding electrode are alternately disposed, the fluid state of a fluid substance flowing in the piping can be decided in a more ensured manner.
According to the fourth aspect of the invention, in addition to effects of the third aspect of the invention, because the measuring electrode and the grounding electrode are wound to be spiral along a flow direction, the fluid state of a fluid substance flowing in the piping can be decided in a more ensured and facilitated manner.
According to the fifth aspect of the invention, in addition to effects of the first to fourth aspects of the invention, depending on a result of the decision of the fluid state, control means is adapted to control adjust means, so that the fluid state of a fluid substance flowing in the path can be surely and easily controlled.
According to the sixth aspect of the invention, in addition to effects of the fifth aspect of the invention, the control means is adapted, when the detected variation of electrostatic capacity is within a set value of a reference variation of electrostatic capacity, to open the first open-close valve and close the second open-close valve and, when the detected variation of electrostatic capacity exceeds the set value of the reference variation of electrostatic capacity, to close the first open-close valve and open the second open-close valve.
Accordingly, when the fluid state of a fluid substance flowing through the path in the piping is normal or the fluid substance is not changed in kind and if the detected variation of electrostatic capacity is within a set value of a reference variation of electrostatic capacity, it is possible to conduct the fluid substance from the piping to a substance take-out machine and surely take out of the substance take-out machine the fluid substance of a normal fluid state or of an unchanged kind. Further, when the fluid state of a fluid substance flowing through the path in the piping is abnormal or the fluid substance is changed in kind and if the detected variation of electrostatic capacity exceeds the set value of the reference variation of electrostatic capacity, it is possible to- stop conducting the fluid substance from the piping to the substance take-out machine and surely conduct the fluid substance of an abnormal fluid state or of a changed kind to a branch pipe end.